Machine tool



May 16, 1944. P` s, JACKSQN 2,349,171

' MACHINE TOOL original vFiled Aug. s, 19'40 2 sheets-sheet 1 May 16, 1944. P. s. JACKSON MACHINE TOOL original Filed Aug. s, 1940 2 Sheets-i-Sheet 2 Patented May 16, 1944 MACHINE TOOL Paul S. Jackson, Rockford, Ill.; assignor to Rockford Machine Tool Company, Rockford, Ill., a corporation of Illinois Original application August 3, 1940,--Serial No.

1941, vSerial No. 397,849

6 Claims.

More particularly the invention relates to a machine having control means including a template controlled or tracer valve. This application is a division of my prior application Serial No. 350,996, iiled August 3, 1940.

It is a general object of the invention to provide a new and improved template controlled machine.

Another object is to provide such a template controlled machine with a tool head and means operable at the end of the cutting stroke of the tool to cause the tool to be moved at right angles to its cutting stroke and away from the work so as to clear it from the chips during the return stroke.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, in which:

Fig. l is a diagrammatic view of a hydraulic circuit embodying the features of this invention.

Fig. 2 is a vertical diametrical sectional view of the tracer or duplicator valve embodied in the circuit of Fig. l. 4

Fig. 3 is an end elevational view of the valve of Fig. 2 taken from the right in that figure.

Fig. 4 is a development better to show the ports of the valve of Fig. 2.

Fig. 5 is a. transverse sectional view of the sleeve and cylinder only of the valve, taken approximately along the line 5--5 of Figs. 2 and 4.

Fig. 6 is a view similar to Fig. 5, but taken along the line 6--6 of Figs. 2 and 4.

For purpose of disclosure, the invention is here shown and will hereinafter be described as applied to a Shaper of the kind fully disclosed and claimed in my United States Letters Patent No. 2,223,038 issued November 26, 1940. Such a shaper has a horizontally disposed, longitudinally reciprocable tool carrying slide or ram III driven by a hydraulic motor I|2 of the reciprocatory type comprising a cylinder I3 fixed in the bed or frame of the shaper, and a piston I|4 whose connecting rod I|5 projects through the forward end of the cylinder I|3 and is secured at its projecting end to the slide III. Through a suitable hydraulic circuit including a pressure generating pump and control valves allk fully disclosed in my above mentioned patent, the slide III is continuously reciprocated, once operation of the shaper is initiated, to move through aforward or cutting stroke and a return stroke repeatedly. 1

Disposed at the front of the shaper and beneath the slide III is a table IIS which, in the Divided and this application June 13,

present instance, constitutes a support for both a template T and a work blank W which is'to be machined to conform to the template T. This table is indexable transversely of the shaper so as to present a new portion of the work to the tool after each cutting stroke of the slide III. Such indexing of the table is effected automatically to take place after the completion of one cutting stroke and before the commencement of the new cutting stroke, all as described in my above mentioned patent.

Mounted on the forward end of the slide III is a tool slide Il'i adapted to carry a cutting tool IIB. In the preesnt instance. this tool slide is mounted for vertical movement and is adapted to be moved through the medium of a hydraulic motor IIS of the reciprocatory type `comprising a cylinder |20 rigid with the slide I I'I and a piston i2| having the projecting end of its piston rod |22 fixed in the main slide II I. Serving partially to counter-balance the weight of the slide Ill is a tension spring |23 secured at one end to the slide II'I, and secured at the other end to an upwardly extending bracket |24 of the slide IIi.

Operating uid is supplied to the motor IIS by a hydraulic circuit which includes a duplicator or tracer valve |25. This valve is mounted to partake of the'same movement as the tool slide II'I and to that end the slide II'l has a forwardly projecting extension |26 supporting on its free end a slide |21 in which the valve |25 is carried. In order that the valve |25 may be adjusted rela.- tive to the tool II8, the slide |21 is vertically movable and may be adjusted through a conventional adjusting screw |28. While the valve |25 is fully disclosed and claimed in my' copending applications Serial Nos. 350,995 and 350,996 filed August 3, 1940, the valve herein will be described in detail in order to render more readily understandable certain features of this invention.

The valve |25 comprises an elongated housing composed in the main by a generally cylindrical casing I5 having extending longitudinally lthereof a bore I6 opening through opposite ends. Opening through the sidesof the casing I5Ka're a plurality of ports I1, I8 and I9. The'wfirst of these ports, namely, I'l, communicateg'iiit fthe bore in the casing I5 through a shallow an fomparatively narrow annular groove 20 andic'onstitutes the intake port through which fluidunder pressure is supplied to the valve. Ports I8 and i9 communicate with the bore I6, respectively,

through shallow and very wide annular grooves 2| and 22, and these ports serve alternately as supply or return ports for the reversible hydraulic motor II9. Secured to the casing I5, as by bolts 23, is a block 24 having formed therein threaded recesses 25, 26 and 21 which register. respectively, with the ports I1, I8 and I9 and constitute means for the attachment of conduits to the valve.

Within the bore of the casing I is an annular sleeve 30 and within the sleeve 30 is a valve cylinder 3| having a passage 32 extending longitudinally thereof. At the end opposite the port I1, the valve cylinder 3| is formed with an external annular groove 33 which communicates with the passage 32 through a plurality of radial ports 34 and which registers with a plurality of radial ports 35 formed in the sleeve 30 so as to communicate with the intake port I1. The remainder of each the sleeve 30 and the cylinder 3| is given over to ports governing the fiow of fluid from the passage 32 within the valve cylinder to the ports I3 and I9.

In order to attain certain advantages which will presently become more apparent, and in order that the valve may act as a reversing valve, the sleeve 30 is formed with a first set of ports taking the form of a plurality of parallel elongated slots 36 cut completely through the sleeve. These slots spiral about the sleeve to form helical ports and are spaced uniformly about the sleeve. A second set of ports is composed of similar slots 31 which, however, spiral in the opposite direction and, moreover, are offset angularly the appropriate amount necessary to make the valve function as a reversing valve, herein about onetenth revolution. A plurality of such slots 36 and 31 are employed so as to increase the volume of fluid which may flow through the valve. Y,

Correspondingly, the valve cylinder 3| has a first and a second set of ports taking the form of parallel, elongated slots 38 and 39, respectively, cut completely through the cylinder to communicate with passage 32 and thus constitute supply or pressure ports. The slots 38 and 39 are also helical and extend generally parallel with their cooperating slots 36 and 31 formed in the sleeve 30, that is, slots 38 and 39 spiral in opposite directions about the valve. Milled ln the outer surface of the cylinder 30 between the slots 38 are a plurality of grooves 46 extending parallel with the slots 38 and between the slots 39 are grooves 40' extending parallel with the slots 39. Unlike the slots 38 and 39, which are independent of one another, the grooves 40 and 40 join at theirv inner ends to form a continuous groove, and grooves 4U moreover open through the end of the cylinder 3| to discharge to an exhaust chamber 4I formed in the major part by a cup-shaped member 42. Thismember is secured over the end of the casing I5 by bolts 43 to close the same. Opening through the side of the member 42 is a port 44 threaded for the reception of a suitable fiuid exhaust or return conduit.

As can be readily understood from the4 foregoing description, and as can easily be seen from a consideration of Figs. 4, 5, and 6, the valve has a neutral or closed position in which none of the slots 36 or 31 registers with any of the slots 38 and 39 on the grooves 40 and 4I'. No fiow of fluid, therefore, can take place. With relative rotation between the sleeve 30 and the cylinder 3| ,v

however, the ports 36 and 31 are brought into registry with the ports in the cylinder. With relative rotation in one direction, the ports 36 register with slots 38 so that pressure fluid is supplied to port I9 whlle ports 31 register with grooves 40' to take care of fluid returning through port I8. Conversely, upon relative rotation in the opposite direction, port I8 becomes a supply or discharge port, while I9 becomes a return port.

To obtain maximum rates of port opening and closing, both the sleeve 30 and the cylinder 3l are rotatable. In order that both may be independently actuated from a point externally of the valve casing, the sleeve 30 has bolted to one end thereof an annular member 41 having a hub portion 48 received in the sleeve, and a radially outwardly projecting flange 49. The flange 49 provides a convenient area through which bolts 50 securing the member tothe sleeve may be passed and also extends radially outwardly beyond the sleeve 30 to engage a shoulder 5I formed in the end of the casing I5. Surrounding the member 41 is an annular ring 52 which is bolted to the casing I5 and bears against the fiange 49 to retain the sleeve against endwise movement. An inturned flange 53 on the ring forms with the member 41 an annular space 54 for trapping leakage fluid. Opening through the ring 52 is a port 52 (see Fig. l) adapted for the attachment of a suction conduit for the removal of trapped leakage fluid. Outwardly of the member 41 is a lever 55 having an annular hub portion 56 bolted to the member 41 to complete the actuating means for the sleeve 30.

The cylinder 3| has a shaft-like extension 59 which projects rotatably through the member 41 and the hub 56 of the lever 55. At its projecting end the extension is splined to receive non-rotatably a lever 60 by which the cylinder is rotated. The lever 60 is retained against movement ofi the end of the extension by a set screw 6I.

Since the valve is particularly adapted for and is herein shown governing the hydraulic circuit of a pattern controlled machine, it includes tracer means for effecting the rotation of the sleeve 39 and the cylinder 3l. Depending from the valve casing I5 is a bracket 65 having a bore 66 therein in which is reciprocably mounted a tracer finger 61. The tracer finger 61 is adapted to project at both ends from the bore and at its outer end has an enlarged head 68 which terminates in a. point the very tip of which is preferably formed by a ball 69 of hardened material, which ball forms the point of contact with a master template T, the contour of which is to be reproduced. The tracer finger 61 is urged outwardly so as to maintain its contact with the template T by a compression spring 1I which encircles the finger and bears at one end against an annular shoulder formed by the head 68, and at the other end bears against an annular shoulder formed in the bracket 65 by a reduction in the diameter of the bore 66.

At its inner end, the nger 61 is bifurcated, and received between the bifurcations 12 and retained therebetween by a pin 13 is a bar 1.4 extending transversely of the valve. One end of the bar is connected by a link 15 to the lever 55 rigid with the sleeve 39, while the other end of the bar 14 is connected by suitable linkage, generally designated 16, to the lever 60 which is non-rotatably mounted on the extension 59 of the cylinder 3|. It will be seen, therefore, that with the slightest movement of the tracer finger' 61 both the sleeve 30 and the cylinder 3| will be rotated and will, moreover, be rotated in opposite directions so as to result in a port opening at twice the rate that would be e'ected by the rotation of either the cylinder or the sleeve alone. Thus, should the template' T cause the finger 61 to move upwardly from a neutral position in which it is shown, the lever 55 would be rotated in a clockwise direction, as viewed in Fig. 3, while the lever 60 would be rotated in a counter-clockwise direction. Such rotation of the levers would,

of course, impart like rotation to the sleeve 30 and the cylinder 3l which, as best seen in Figs. 5 and 6, would `cause the ports 36 in the sleeve to register with the return grooves -49 in the cylinder, making of the port ls a return port, while the ports 31 in the other half of the sleeve (see Fig. 6) would register with the grooves 39, making of the port I8 a pressure or supply port. As will presently be seen, when I8 is a pressure port, fiuid is supplied to the hydraulic motor H9 in such direction as to cause the tool to be raised an amount corresponding to the movement of the tracer nger 61. It is to be understood, of course, that with the valve mounted to move with the tool that at the time the tool is raised a proper amount the tracer finger will again be in neutral position and the sleeve and the cylinder will have returned to the position shown in Figs. 5 and 6, cutting of the supply of operating fluid. Conversely, should the tracer finger 61 drop from its neutral position, the levers 55 and 60 would be rotated in a counter-clockwise and clockwise direction, respectively, and the sleeve and the cylinder would be given a corresponding rotation. Under those conditions, the ports 36 in the sleeve would register with the grooves 38 in the cylinder, making of the port I9 a pressure port, while the ports 31 in the other half of the sleeve would register with the grooves 40 to make of the port I8 a return port.

The valve herein is provided with lcertain adjustments which, in conjunction with the helical character of the ports, serves to permit Such setting of the valve as will aid in counter-balancing the mechanism controlled thereby, and for other proper setting and operation of the mechanism. To that end, the linkage 1B is made adjustable and comprises a somewhat triangular shaped link 11 which is pivotally connected at its apex to the lever 60 and near its base is formed withan arcuate slot 18. Cooperating with the link 11 is a link 1.9 pivotally connected at one end to an end of the bar 14, and pivotally connected at its other end through the medium of a pin 80 to the link 11 near its point of connection to the lever 60 and to one side of the center line of the link; Carried by the link 19 and projecting through the slot 18 is a bolt 8| which may be loosened to permit swinging of the links relative to one another and thereafter tightened to retain the links in adjusted position. This adjustment makes possible a variation in the counter-balancing eiect on the tool actuating motor I I9 of the uid flowing through the valve. Thus, with port i8 leading to that end of the hydraulic motor which serves to support or raise the tool, the valve may be appropriately adjusted to effect an increasing or decreasing counter-balancing effect. This is best understood from a consideration of Fig. 4. For any given setting of the tracer finger 61, if the linkage 16 is adjusted so as to increase its eiective length, the lever 60 and hence the cylinder will be rotated in a counterclockwise direction, as viewed in Fig. 3, which is downwardly, as viewed in the development (Fig. 4).* With such downward movement of the cylinder, the pressure ports 39 will be moved-toward the ports 31 in the sleeve, while the pressure ports 75 38 in the left half of the cylinder will be moved away from the ports 36. Thus it will be seen that, for any given movement of the tracer nger 61 above or below its normalposition, the ports 31 and 39 will come into registry sooner or have a greater registry, if indeed they are not in registry when the tracer finger is in its neutral position, with an up movement of the finger than the ports 36 and 39 for a corresponding downward movement of the finger.

Means is also provided for adjusting the cylinder longitudinally relative to the sleeve 30. To that end, the cup-shaped member 42 has formed therein a threaded bore 83 in the bottom thereof in which is threadedly received a plug 84. The cylinder 3| has a reduced rod-like extension 85 which passes through and by means of which the cylinder is secured to the plug 84. In order that the cylinder, though attached to the plug, may be freely rotatable, there is interposed between the cylinder and the plug a bali bearing 86 and a similar ball bearing 81 is interposed between the plug and a nut 88 threaded onto the extension 85, and by means of which the cylinder is secured to the plug 84 to partake of the axial movement of the plug. A lock nut 89 secures the plug in adjusted position, and the adjusting mechanism is protected against injury and accidental shifting by a cap 90 threaded onto a hub-like ange 9| projecting outwardly from the member 42. It will be apparent that by rotation of the plug 8d the cylinder 3l will be moved axially relative to the sleeve 39. As best seen from the development of Fig. 4, such axial shifting of the cylinder relative to the sleeve for any given setting of the valve and tracer nger will cause a greater or lesser overlap between the ports in the sleeve and either both pressure ports in the cylinder or both return grooves, depending upon in which direction the shift is made.

Means is provided forvmanually raising and holding the tracer finger 61 above its neutral position, so as to cause the valve to remain in an open position. To that end, there is rotatably journaled in the bracket 65 a shaft 92. This shaft at its inner end carries an eccentrically mounted nub 93 which projects into the reduced portion of the bore 66 and into a slot 94 formed in the tracer finger 61. At its outer end the shaft 92 carries a knurled hand knob 95. Normally the shaft is rotated to the position shown in Fig. 2, in which the nub 93 merely serves as a limit for the movements, particularly the outward movement of the tracer finger 61. When rotated through 180, however, the nub 93 shifts the tracer finger inwardly and holds the same there, thereby rotating the sleeve 30 in a clockwise direction, as viewed in Fig. 6, and the cylinder 3l in a counter-clockwise direction. causing a registration of ports 31 and 39. Pressure fluid is thus supplied to the port i8 until the shaft 92 is manually rotated to restoretne tracer nger to normal, freely operative position.

Means is also provided for automatically raising and holding the tracer finger 61 above its neutral position for a limited time. This means takes the form of a crank 95 pivotally mounted between ears 91 formed on the bracket 65 and having a rst leg 98 adapted to abut the bracket 65 to limit the counterclockwise rotation of the crank, and a second leg 99 which projects into a notch |09 cut in the tracer nger 61. Projecting downwardly and outwardly from' the end of the'leg 99 is a -nger Il which, upon striking an abutment on the template such as indicated at T' during the movement of the tracer finger across the template, will pivot the crank in a clockwise direction as viewed in Fig. 2, and as a result will raise the tracer finger 61. Such raising of the tracer finger will, of course, rotate the sleeve and cylinder of the valve to open the ports therein. Herein the valve is so connected that raising of the tracer finger will cause a like raising movement of the tool. Hence the abutment T' on the template is normally so positioned that it will be struck by the finger at the end of the cutting stroke of the tool and frequently when the tool comes to a hub or the like, so that it will be raised to clear itself from the chips cut by it. Occurring at the end of the stroke, the crank is, of course, pivoted until a reversal takes place, after which time the tracer finger again is freed to the control of the template proper. In addition to clearing the tool from the chips which it has cut, this construction has the advantage that it raises the tool out of contact with the work during the return stroke.

In addition to the tracer'valve |25, the hydraulic circuit comprises la main pressure pump |30 driven from an electric motor |3I. The pump |30 draws fluid from a tank or reservoir R through a conduit |32 and discharges the pres sure fluid through a conduit |33 which leads to the intake port |1 of the valve |25. Interposed in the conduit |33 is a relief valve |34 which has leading therefrom a by-pass return conduit |35 through which excess fluid is returned to the reservoir when the pressure in the conduit |33 exceeds a predetermined value. A cooler |36 may be connected to the conduit |35 in conventional manner to cool the fluid.

Valve |25 has its port i8 connected to the head end of the tool slide actuating motor ||9 by a conduit |31, while the rod end of the motor ||9 is connected by a conduit |38 with the port i9 of the valve. It is to be noted in this connection that the motor ||9 is so arranged that the larger pressure area of the piston |2| serves to effect a raising of the slide ||1 so that the pressure differential between the head and rod ends of the motor may be utilized to aid in counter-balancing the weight of the slide |1 and the parts carried thereby. Exhaust fluid is returned from the valve to the reservoir R through a conduit |39 connected at one end to the port 44 and discharging at the other end to the reservoir R. Preferably interposed in this return conduit is a back pressure valve |40.

Also driven from the motor |3| is an auxiliary pump |4| which is a small suction pump. This pump has connected to its intake side a conduit |42 which is connected to the port 52' of the valve |25 for the purpose not only of withdrawing leakage fluid trapped in the chamber 54, but for actually maintaining slight suction in the chamber so as to preclude all possibility of a building up of pressure within the valve by leakage fluid. A conduit |43 leads from the discharge side of the pump |4| to the reservoir R. In order to maintain the suction of the pump |4|, a conduit |44 is connected at one end to the conduit |42 and at the other end is connected with the reservoir so that fluid may be continuously circulated through the pump |4|.

In the operation of the machine to which the circuit is applied, a woik blank W is rst mounted on the table I6 and to the tool ||8 adjusted relative to the neutral setting of the tracer finger 61, so as to produce the desired depth of cut. The machine is then started and the slide will move through a forward or cutting stroke. During such forward or cutting stroke, the tracer finger 61, of course, traverses the template T, while at the same time the tool ||3 traverses the work W. With a, template of the contour here shown, the tracer finger 61 will initially move below its normal'position and accordingly will rotate the sleeve 30 in a counter-clockwise direction and the cylinder 3| in a clockwise direction, as viewed in Figs. 5 and 6, thereby causing ports 33 in the sleeve to register with the pressure ports 36 in the cylinder and ports 31 of the sleeve to register with return ports ,40' in the cylinder. Consequently, port i9 becomes a pressure port and fluid is supplied to the rod end of the cylinder |20, while i3 is a return port through which fluid is discharged from the head end of the cylinder. 'I'he tool slide ||1, therefore, moves downwardly carrying with it the valve |25 until the tracer finger 81 again is returned to neutral or normal position in which the valve |25 is closed arresting the further supply of uid to the motor ||9. When the tracer 4`finger 31 strikes a point in the template raising it above its neutral or normal position, the sleeve and the cylinder 3| of the valve are rotated in the opposite directions, namely, clockwise and counter-clockwise, respectively, as viewed in Figs. 5 and 6. With rotation in those directions, the ports in the sleeve and the valve cylinder are caused to register in a reverse manner, thereby making of the port i0 a pressure port, while the port I9 becomes a return port and fluid is thus supplied to the head end of the cylinder |20 so as to raise the tool slide and the valve until the tracer finger again reaches its normal or neutral position. It is to be understood, of course, that whatever the contour of the template, the valve |25 will so control the supply of fluid to the motor 9 as to cause the tool ||8 to take a cut corresponding to the contour of the template.

At the end of the cutting stroke the nger |0| of the crank 96 strikes the abutment T' of the template, and in so doing shifts the tracer finger upwardly and thus rotates the valve in such manner as to cause fluid to be supplied to the head end of the motor 9. This raises the tool slide ||1 and thus permits it to clear itself from the chips which it has cut, and this control and resultant movement of the tool slide is particularly advantageous when the cut of the tool terminates up against a hub or like structure. The tracer finger, of course, remains shifted until the finger 0| is withdrawn from engagement with the abutment T as an incident to the return movement of the slide During the return stroke of the slide and after the linger |0| has been freed from engagement with the abutment T', the tool slide ||1 floats down to a more or less normal position preparatory to commencement of a successive cutting stroke. Thus the raising of the tool slide at the end of the cutting stroke has the additional advantage of lifting the tool oiT of the work during the return stroke of the tool.

Should it be found, during the operation of the machine, that the tool slide i|1 and the other parts carried thereby is not quite properly counter-balanced by the spring |23, this may be compensated for by an adjustment of the linkage 16 of the valve. Thus should the counter-balancing effect of the spring |23 be insufficient the linkage 1.6 may be lengthened so that for a given setting of the tracer finger 61 the cylinder 3| will have a position slightly counter-clockwise,

as viewed in Figs. and 6, of its normal position. Such adjustment, as will readily be seen from Figs. 4 to 6, brings the pressure ports 39 and the ports 31 closer together, while the pressure ports 38 and the ports 36 are separated, and since the ports 31 lead to the port I8 connected to the head end of the cylinder |20, it will be seen that this adjustment will tend to cause the fluid supplied to the motor H9 to have a greater lifting eiect on the slide H1. Conversely, by shortening the linkage 16 the counter-balancing effect of the uid can be made less. Also, should the slide I l1 be somewhat sluggish in its response to shift of the tracer finger 81, this may be corrected by adjusting the cylinder 3l axially relative to the sleeve 30, thereby varying the overlap of the ports.

I claim as my invention:

l. In a template controlled machine, a template, a work support, a recim'ocable main slide, means for driving said slide through a cutting and a return stroke relative to said template and to said Work support, a tool slide mounted on said main slide for movement transversely thereof, a hydraulic motor for actuating said tool slide, a tracer mechanism mounted on said tool slide and having a tracer nnger adapted to ride on the template and a valve controlled by said finger, a hydraulic circuit including said motor and said valve, and means carried by said tracer mechanism operable upon engagement with an abutment at the end of the cutting stroke to move said tracer finger out of engagement with the template to effect a corresponding movement of the tool slide.

2. In a template controlled machine, a reciprocable main slide, means for driving said slide through a cutting and a return stroke. a tool slide mounted on said main slide for movement transversely thereof, a hydraulic motor for actuating said tool slide, a tracer valve mounted on said tool slide and having a tracer linger adapted to ride on the template, a hydraulic circuit including said motor and said valve, and means operable upon engagement with an abutment on the template at the end of the cutting stroke to raise said tracer nger out of engagement with the template to effect a like raising of the tool slide, said means comprising a crank 'pivoted on the valve casing and having a leg disposed to engage and shirt said tracer iinger away from the template when said crank is rocked, and a linger on said crank projecting laterally oi said tracer linger to rock said crank upon engagement with an abutment on the template.

3. In a template controlled machine, a support for a template and for a work piece, a reciprocable main slide, means for driving said slide through a cutting and a return stroke relatively to said support, a tool slide mounted for movement transversely thereof, a hydraulic motor for actuating said tool slide, a tracer valve mounted on said tool slide and having a tracer finger adapted to ride on the template, -a hydraulic circuit including said motor and said valve, and means operable upon engagement with an abutment at the end of the cutting stroke to move said tracer nger o'ut of engagement with the template to eilect a like movement of the tool slide away from the main slide, said means comprising a crank pivoted on the valve casing and having a leg disposed to engage and shift said tracer finger away from the template when said crank is rocked, and a ilnger on said crank projecting laterally of said tracer finger to rock said crank upon engagement with an abutment.

4. In a template controlled machine, a template, a work support, a reciprocable main slide, means for driving said slide through a cutting and a return stroke relative to said work support and said template, a tool slide mounted for movement transversely of said main slide, a hydraulic motor for actuating said tool slide, a tracer valve mounted on said tool slide and having a tracer linger adapted to rideon said template, a hydraulic circuit including said motor and said valve,k and means operable upon engagement with an abutment at the end of the cutting stroke to move said tracer linger out of engagement with the template to eilect a like movement of the tool slide transversely of the main slide to carry a tool on the tool slide out of engagement with a work piece on said support during the return stroke of said main slide.

5. In a template controlled machine, a work support having a template thereon, a tool sup .port mounted for movement relatively to the fwork support, a hydraulic motor for actuating 1 said tool support, a tracer valve mounted on said tool support and having a tracer linger adapted to ride on the template, a hydraulic circuit including said motor and said valve, and means operable upon engagement with an abutment on the template at the end of a cutting operation to move said tracer finger away from the template to effect a like movement o! a tool on the tool support away from the work on the work support.

6. In a template controlled machine, a support for a template and for a work piece, a reciprocable main slide, means for driving said slide through a cutting and a return stroke relatively to said work support, a tool suDDOrt on said main slide, a hydraulic motor for actuating one of said work and said tool supports to eil'ect relative movement toward one another, a tracer mechanism movable with said tool support and having a tracer ilnger adapted to ride on the PAUL B. JACKSON. 

